11 ms·

The Secret Life of XY Monitors (2001)

98 points by ibobev 3y ago

h2odragon 3y ago
> Very likely, the real story is simply that the potting material used in the transformers was not up to the task. Regardless of the cause, by the time the problem appeared the Operators had already made a good return on their investment. That was good news for the Operators but bad news for those of us trying to keep their 17 year-old Star Wars games alive. I was a big fan of the "star wars" consoles; and they all had a peculiar smell. now i know what that was. cooking flybacks.
onetimeuse92304 3y ago
> It's also a safety issue, since the Cathode voltage might be substantial. When I was a small kid, my father had a TV set repair side hustle. I was 7-8yo but I would sometimes be called to help him a bit. Once he asked me to clean a bunch of CRT tubes from substantial amount of dust. What he forgot is that he was just testing one of them and the charge wasn't properly dissipated and it did not have time to dissipate on its own. I got hit with a spark so powerful, that it must have temporarily disrupted my brain because for a brief moment I was completely stupefied, and then I just resumed cleaning it. Then I got hit for the second time, then for the third time. Only after third time I realised that me cleaning the tube has something to do with it. Probably the discharge was much less powerful the third time and did not stun me completely. I can tell you the voltage and amount of charge on these things is no joke. Multiple tens of thousands of volts is enough to stun you temporarily. Probably not enough to cause lasting damage unless you are extremely unlucky about where the discharge went (stun guns usually have higher voltage and capacity), but enough for you to lose control of your body, fall and hurt yourself.
- colechristensen 3y ago
  >Probably not enough to cause lasting damage unless you are extremely unlucky about where the discharge went You don't have to be that unlucky. Discharge across your heart can stop it, no problem. It is not at all difficult for that energy to route through your chest. You were lucky.
  - onetimeuse92304 3y ago
    Well... one difference between a stun gun and CRT tube is that in a stun gun you usually have both terminals relatively close to each other. Little chance of the main pulse going deep across the chest. On the other hand working with the CRT you are likely using both hands and that makes the signal go through your upper chest, by default. So yeah, there is something to it. One thing I learned as amateur EE is to always use just one hand to probe the device under test if there is any high voltage or AC involved. You put the other hand behind you so that there is no chance you create a short right through your chest.
    - Scoundreller 3y ago
      And have someone nearby with a 2x4 to beat you off whatever you might be gripping/fell onto.
      - sowbug 3y ago
        Just to add a bit more color here: most flexor muscles in your body are a lot stronger than the corresponding extensors, so when an external command comes in telling both to contract, for example from electricity in the thing you're working on, gripping wins. You can't let go. Great for grabbing a branch as you fall out of a tree. Not so great for repairing a power line. Late edit: I've heard you can use this factoid to your advantage to avoid being eaten by an alligator or crocodile. Wrap your arms around its snout and hold on for dear life. Their jaws are strong enough to snap you in two, but not enough to force themselves open when you're holding them shut. I don't know what Step Two is, unfortunately.
        jareklupinski 3y ago
        > I don't know what Step Two is, unfortunately. step two is waiting for the aforementioned 2x4 wielder "to beat ... whatever you might be gripping/fell onto"
        rzzzt 3y ago
- orbital-decay 3y ago
  I also touched a CRT anode when fiddling with a TV set when I was 12. I was aware of the danger and scared of that thing (it was huge!) but still forgot to discharge it. Despite the ~26kV nominal voltage there was only enough charge to make me jump to the ceiling, or at least I thought so. It's a lesson you never forget.
- deleted 3y ago
  [deleted]
- LorenPechtel 3y ago
  I got zapped once as a kid. My grandfather's TV, I was pulling the tubes to take them to the testing machine. Fairly small screen but I knew it probably had some residual charge that I most definitely didn't want to come into contact with. The layout was such that I could pull the tubes while staying far away from it. It never occurred to me that safety would require keeping him from looking on in curiosity and bumping my arm. (He was impatient about getting his TV fixed, I saw that whoever designed it had had the courtesy to put the tubes in an area where even if your hand slipped it wouldn't approach the tube. That was no protection against my hand getting moved in a direction I was not applying force, though.) I don't think such things are actually capable of direct lasting damage but you do lose control--I slammed my hand into the cabinet pretty hard, completely involuntary. My understanding is that tasers are AC, thus involuntary movements will be back and forth rather than just in one direction.
  - bb611 3y ago
    > My understanding is that tasers are AC, thus involuntary movements will be back and forth rather than just in one direction. Tasers AC output is at low frequency but still significantly faster than human muscles can move, if you watch any video of a tase you'll see it causes the victim's muscles to seize up and not oscillate.
- lttlrck 3y ago
  I was thrown across a room twatting around in the back of a TV. Many years later I still wonder if there were any sdiefeftcs.
  - rokkitmensch 3y ago
    "I don't hire programmers who spell correctly, I hire programmers who misspell consistently" or how does it go
tyingq 3y ago
Oscilloscopes are mentioned a few times, but not for the main reason I assumed they would be. Many of them include an x/y mode to use them as vector displays, even some of the cheap ~$150 ones.
- theamk 3y ago
  TIL: even today, they still make analog oscilloscopes [0] The are not cheap though - almost $1000 for a 30MHz model which is super expensive, especially compared to digital model. I assume "$150" refer to price for a used oscilloscope. [0] https://www.bkprecision.com/products/data-acquisition-recorders-loggers/2120C https://www.bkprecision.com/products/data-acquisition-record...
  - tyingq 3y ago
    $150 for a new, cheap/small digital oscope that supports an X/Y mode. Yes, it's not truly a vector display, but accepts vector x/y input and rasterizes it. Not all of these have an X/Y mode though, so check first. But, yes,old oscopes with CRTs is an option also.
RespectYourself 3y ago
The glow of CRTs creates an atmosphere that's surely missed by a lot of those who enjoyed arcades.
RetroTechie 3y ago
It's a pity such monitors aren't made any more. In the late 80s, I owned a small (12..13" or so) amber monochrome CRT monitor. Lovely phosphor color, non-flickering superb for text-based work, single composite video input. Let go when it didn't seem to matter much, and CRTs were still everywhere. But today I'd love to have such a screen. Commercially this would be a small niche market, but probably a stable one. And regardless of modern LCD/LED screens, such antique monochrome CRTs have properties that no modern flatscreen can match. As an in-between, LCD/LED screen designed for ~0 lag & X/Y vector input (monochrome or color), would be nice too. Doesn't exist afaik?
- autoexec 3y ago
  When LCD monitors/TVs came out they were a huge step backwards in terms of quality. They were relentlessly pushed on consumers because they were cheaper to make, cheaper to ship, and took up less space in stockrooms and on store shelves. I doubt the CRT will make a comeback. Even today's TVs are inferior to CRTs in some ways and so we're still compromising, but at least current LCD screens are so much better now than they were when they were replacing CRTs.
  - bombcar 3y ago
    The problem is that the available market for CRT screens (and it does exist!) is well supplied for now by used and other older models. Modern screens are better in many ways, but like CRTs, there are tradeoffs and many things are not yet designed around those tradeoffs.
    - actionfromafar 3y ago
      Not well supplied at all. None of the three sub-sects are well provided: a) high-quality video monitors like Sony PMW, great for gaming and old-school video b) slow amber screens like mentioned above c) large TV sets with good colors (and no semi-digital stuff messing with quality like 100Hz) None of those can be easily found, especially not in working condition. Oh, forgot about the substantial d) Gaming CRT with insane refresh-rate and true blacks! Of these, I think only monochrome sets and maaaaaaybe PMW-style sets have any inkling of a chance of new manufacture. Probably only monochrome monitors, they are much simpler to get right.
rbanffy 3y ago
It's a shame that when the SCART connector was conceived they didn't include X and Y signals along with the RGB ones. Would be cool to have every TV in Europe also being an X-Y monitor (and allow an extra cool free visualization mode when the TV is on but you are listening to music).
- dfox 3y ago
  The deflection circuitry of a TV or raster-scan CRT monitor is not designed to be driven by random X-Y signals and optimized around the sawtooth patterns of the raster scan. One thing is that driving the deflection coils of large-ish CRT at typical raster scan frequencies requires considerable power (the typical X-Y display cannot draw all the "pixels" each "frame") and another is that there is a bunch of analog tricks (funky magnetics in the "output filters" and such) where various non-linearities of the system partially cancel each other out, which works only for the typical saw-tooth-ish deflection waveforms. Another thing is that both CRT monitors and "modern" CRT TVs synchronize both their main SMPS and the EHT flyback to horizontal frequency of displayed image (one is tempted to say that typical CRT computer monitor is in fact one giant overcomplicated SMPS). The reasoning is more or less the same as to why the TV framerate is related to mains frequency: reduction of artifacts that move around in the image. Also, this is the reason why out-of-spec signal can damage (old, which essentially means not microprocessor controlled) CRT displays and TVs.
dn3500 3y ago
I used to have a 1948 Hallicrafters TV and it had yet another type of high voltage supply. There was a 100 kHz oscillator driving an air-core transformer in normal (not flyback) mode. The potting had gone bad on the transformer, and I couldn't find a suitable replacement, but I did find one that had the right secondary winding. Since it was air-core I just cut the secondary off that and the primary off the original and glued them together. Worked great.
- HeyLaughingBoy 3y ago
  Hallicrafters made TVs? I guess I shouldn't be surprised but I've only ever heard that name in the context of ham radio and shortwave listening.
xythobuz 3y ago
I just want to mention Oscilloscope Music [1]. You can find other artists on YouTube. It can be played on analog oscilloscopes with an XY mode. I also recently made a little player with a Raspberry Pi [2]. [1]: https://oscilloscopemusic.com/ https://oscilloscopemusic.com/ [2]: https://www.xythobuz.de/osci_music_player.html https://www.xythobuz.de/osci_music_player.html
sam1r 3y ago
It's absolutely worthwhile to click the comments link. [0] [0] https://www.jmargolin.com/mail.htm https://www.jmargolin.com/mail.htm
Mountain_Skies 3y ago
Always wondered how difficult it would be to hook up one of the old multicolor vector screens to an emulator and be able to play games like Star Wars and Asteroids in true vector presentation instead of a raster approximation. Going to guess the emulator would need a completely different rendering subsystem and the computer would need a custom video out to drive the vector monitor. Maybe without a good source of working multicolor vector monitors it wouldn't be worth the effort but it would be nice to have something closer to the real deal without needing to collect a large number of cabinets.
- puddingcat 3y ago
  Back in the early '00s there was such a device - the Zector ZVG. It was driven via parallel port and used a custom version of MAME. I'm sure somebody in the VAC scene started work on a replacement after these ended production. I had an ZVG and it was pretty good. But now I just play my Star Wars cockpit.
CliffStoll 3y ago
A decade ago, I taught physics to some high school students; they were amazed by the old CRT Tektronix oscilloscope. "So many knobs and controls!" "Does it only show green?" "Can it show pictures from the web?" Two of them figured it out and we used it to measure the speed of sound. Recently, I dusted it off and let a couple neighbor teenagers fool with it (displaying speech, music, sine waves, and Lissajoius patterns. Again, they were fascinated. Good stuff there!
- rnewme 3y ago
  I got raised eyebrow at "pictures from web" a decade ago, but then realized decade ago was '13/14 and not '03/04...
- garaetjjte 3y ago
  >Can it show pictures from the web? Even better, you can play Quake on it! https://www.lofibucket.com/articles/oscilloscope_quake.html https://www.lofibucket.com/articles/oscilloscope_quake.html

98 points by ibobev 3y ago

> Very likely, the real story is simply that the potting material used in the transformers was not up to the task. Regardless of the cause, by the time the problem appeared the Operators had already made a good return on their investment. That was good news for the Operators but bad news for those of us trying to keep their 17 year-old Star Wars games alive. I was a big fan of the "star wars" consoles; and they all had a peculiar smell. now i know what that was. cooking flybacks.

onetimeuse92304 3y ago

> It's also a safety issue, since the Cathode voltage might be substantial. When I was a small kid, my father had a TV set repair side hustle. I was 7-8yo but I would sometimes be called to help him a bit. Once he asked me to clean a bunch of CRT tubes from substantial amount of dust. What he forgot is that he was just testing one of them and the charge wasn't properly dissipated and it did not have time to dissipate on its own. I got hit with a spark so powerful, that it must have temporarily disrupted my brain because for a brief moment I was completely stupefied, and then I just resumed cleaning it. Then I got hit for the second time, then for the third time. Only after third time I realised that me cleaning the tube has something to do with it. Probably the discharge was much less powerful the third time and did not stun me completely. I can tell you the voltage and amount of charge on these things is no joke. Multiple tens of thousands of volts is enough to stun you temporarily. Probably not enough to cause lasting damage unless you are extremely unlucky about where the discharge went (stun guns usually have higher voltage and capacity), but enough for you to lose control of your body, fall and hurt yourself.

colechristensen 3y ago
>Probably not enough to cause lasting damage unless you are extremely unlucky about where the discharge went You don't have to be that unlucky. Discharge across your heart can stop it, no problem. It is not at all difficult for that energy to route through your chest. You were lucky.
- onetimeuse92304 3y ago
  Well... one difference between a stun gun and CRT tube is that in a stun gun you usually have both terminals relatively close to each other. Little chance of the main pulse going deep across the chest. On the other hand working with the CRT you are likely using both hands and that makes the signal go through your upper chest, by default. So yeah, there is something to it. One thing I learned as amateur EE is to always use just one hand to probe the device under test if there is any high voltage or AC involved. You put the other hand behind you so that there is no chance you create a short right through your chest.
  - Scoundreller 3y ago
    And have someone nearby with a 2x4 to beat you off whatever you might be gripping/fell onto.
    - sowbug 3y ago
      Just to add a bit more color here: most flexor muscles in your body are a lot stronger than the corresponding extensors, so when an external command comes in telling both to contract, for example from electricity in the thing you're working on, gripping wins. You can't let go. Great for grabbing a branch as you fall out of a tree. Not so great for repairing a power line. Late edit: I've heard you can use this factoid to your advantage to avoid being eaten by an alligator or crocodile. Wrap your arms around its snout and hold on for dear life. Their jaws are strong enough to snap you in two, but not enough to force themselves open when you're holding them shut. I don't know what Step Two is, unfortunately.
      - jareklupinski 3y ago
        > I don't know what Step Two is, unfortunately. step two is waiting for the aforementioned 2x4 wielder "to beat ... whatever you might be gripping/fell onto"
        rzzzt 3y ago
orbital-decay 3y ago
I also touched a CRT anode when fiddling with a TV set when I was 12. I was aware of the danger and scared of that thing (it was huge!) but still forgot to discharge it. Despite the ~26kV nominal voltage there was only enough charge to make me jump to the ceiling, or at least I thought so. It's a lesson you never forget.
deleted 3y ago
[deleted]
LorenPechtel 3y ago
I got zapped once as a kid. My grandfather's TV, I was pulling the tubes to take them to the testing machine. Fairly small screen but I knew it probably had some residual charge that I most definitely didn't want to come into contact with. The layout was such that I could pull the tubes while staying far away from it. It never occurred to me that safety would require keeping him from looking on in curiosity and bumping my arm. (He was impatient about getting his TV fixed, I saw that whoever designed it had had the courtesy to put the tubes in an area where even if your hand slipped it wouldn't approach the tube. That was no protection against my hand getting moved in a direction I was not applying force, though.) I don't think such things are actually capable of direct lasting damage but you do lose control--I slammed my hand into the cabinet pretty hard, completely involuntary. My understanding is that tasers are AC, thus involuntary movements will be back and forth rather than just in one direction.
- bb611 3y ago
  > My understanding is that tasers are AC, thus involuntary movements will be back and forth rather than just in one direction. Tasers AC output is at low frequency but still significantly faster than human muscles can move, if you watch any video of a tase you'll see it causes the victim's muscles to seize up and not oscillate.
lttlrck 3y ago
I was thrown across a room twatting around in the back of a TV. Many years later I still wonder if there were any sdiefeftcs.
- rokkitmensch 3y ago
  "I don't hire programmers who spell correctly, I hire programmers who misspell consistently" or how does it go

tyingq 3y ago

Oscilloscopes are mentioned a few times, but not for the main reason I assumed they would be. Many of them include an x/y mode to use them as vector displays, even some of the cheap ~$150 ones.

theamk 3y ago
TIL: even today, they still make analog oscilloscopes [0] The are not cheap though - almost $1000 for a 30MHz model which is super expensive, especially compared to digital model. I assume "$150" refer to price for a used oscilloscope. [0] https://www.bkprecision.com/products/data-acquisition-recorders-loggers/2120C https://www.bkprecision.com/products/data-acquisition-record...
- tyingq 3y ago
  $150 for a new, cheap/small digital oscope that supports an X/Y mode. Yes, it's not truly a vector display, but accepts vector x/y input and rasterizes it. Not all of these have an X/Y mode though, so check first. But, yes,old oscopes with CRTs is an option also.

RespectYourself 3y ago

The glow of CRTs creates an atmosphere that's surely missed by a lot of those who enjoyed arcades.

RetroTechie 3y ago

It's a pity such monitors aren't made any more. In the late 80s, I owned a small (12..13" or so) amber monochrome CRT monitor. Lovely phosphor color, non-flickering superb for text-based work, single composite video input. Let go when it didn't seem to matter much, and CRTs were still everywhere. But today I'd love to have such a screen. Commercially this would be a small niche market, but probably a stable one. And regardless of modern LCD/LED screens, such antique monochrome CRTs have properties that no modern flatscreen can match. As an in-between, LCD/LED screen designed for ~0 lag & X/Y vector input (monochrome or color), would be nice too. Doesn't exist afaik?

autoexec 3y ago
When LCD monitors/TVs came out they were a huge step backwards in terms of quality. They were relentlessly pushed on consumers because they were cheaper to make, cheaper to ship, and took up less space in stockrooms and on store shelves. I doubt the CRT will make a comeback. Even today's TVs are inferior to CRTs in some ways and so we're still compromising, but at least current LCD screens are so much better now than they were when they were replacing CRTs.
- bombcar 3y ago
  The problem is that the available market for CRT screens (and it does exist!) is well supplied for now by used and other older models. Modern screens are better in many ways, but like CRTs, there are tradeoffs and many things are not yet designed around those tradeoffs.
  - actionfromafar 3y ago
    Not well supplied at all. None of the three sub-sects are well provided: a) high-quality video monitors like Sony PMW, great for gaming and old-school video b) slow amber screens like mentioned above c) large TV sets with good colors (and no semi-digital stuff messing with quality like 100Hz) None of those can be easily found, especially not in working condition. Oh, forgot about the substantial d) Gaming CRT with insane refresh-rate and true blacks! Of these, I think only monochrome sets and maaaaaaybe PMW-style sets have any inkling of a chance of new manufacture. Probably only monochrome monitors, they are much simpler to get right.

rbanffy 3y ago

It's a shame that when the SCART connector was conceived they didn't include X and Y signals along with the RGB ones. Would be cool to have every TV in Europe also being an X-Y monitor (and allow an extra cool free visualization mode when the TV is on but you are listening to music).

dfox 3y ago
The deflection circuitry of a TV or raster-scan CRT monitor is not designed to be driven by random X-Y signals and optimized around the sawtooth patterns of the raster scan. One thing is that driving the deflection coils of large-ish CRT at typical raster scan frequencies requires considerable power (the typical X-Y display cannot draw all the "pixels" each "frame") and another is that there is a bunch of analog tricks (funky magnetics in the "output filters" and such) where various non-linearities of the system partially cancel each other out, which works only for the typical saw-tooth-ish deflection waveforms. Another thing is that both CRT monitors and "modern" CRT TVs synchronize both their main SMPS and the EHT flyback to horizontal frequency of displayed image (one is tempted to say that typical CRT computer monitor is in fact one giant overcomplicated SMPS). The reasoning is more or less the same as to why the TV framerate is related to mains frequency: reduction of artifacts that move around in the image. Also, this is the reason why out-of-spec signal can damage (old, which essentially means not microprocessor controlled) CRT displays and TVs.

dn3500 3y ago

I used to have a 1948 Hallicrafters TV and it had yet another type of high voltage supply. There was a 100 kHz oscillator driving an air-core transformer in normal (not flyback) mode. The potting had gone bad on the transformer, and I couldn't find a suitable replacement, but I did find one that had the right secondary winding. Since it was air-core I just cut the secondary off that and the primary off the original and glued them together. Worked great.

HeyLaughingBoy 3y ago
Hallicrafters made TVs? I guess I shouldn't be surprised but I've only ever heard that name in the context of ham radio and shortwave listening.

xythobuz 3y ago

I just want to mention Oscilloscope Music [1]. You can find other artists on YouTube. It can be played on analog oscilloscopes with an XY mode. I also recently made a little player with a Raspberry Pi [2]. [1]: https://oscilloscopemusic.com/ https://oscilloscopemusic.com/ [2]: https://www.xythobuz.de/osci_music_player.html https://www.xythobuz.de/osci_music_player.html

sam1r 3y ago

It's absolutely worthwhile to click the comments link. [0] [0] https://www.jmargolin.com/mail.htm https://www.jmargolin.com/mail.htm

Mountain_Skies 3y ago

Always wondered how difficult it would be to hook up one of the old multicolor vector screens to an emulator and be able to play games like Star Wars and Asteroids in true vector presentation instead of a raster approximation. Going to guess the emulator would need a completely different rendering subsystem and the computer would need a custom video out to drive the vector monitor. Maybe without a good source of working multicolor vector monitors it wouldn't be worth the effort but it would be nice to have something closer to the real deal without needing to collect a large number of cabinets.

puddingcat 3y ago
Back in the early '00s there was such a device - the Zector ZVG. It was driven via parallel port and used a custom version of MAME. I'm sure somebody in the VAC scene started work on a replacement after these ended production. I had an ZVG and it was pretty good. But now I just play my Star Wars cockpit.

CliffStoll 3y ago

A decade ago, I taught physics to some high school students; they were amazed by the old CRT Tektronix oscilloscope. "So many knobs and controls!" "Does it only show green?" "Can it show pictures from the web?" Two of them figured it out and we used it to measure the speed of sound. Recently, I dusted it off and let a couple neighbor teenagers fool with it (displaying speech, music, sine waves, and Lissajoius patterns. Again, they were fascinated. Good stuff there!

rnewme 3y ago
I got raised eyebrow at "pictures from web" a decade ago, but then realized decade ago was '13/14 and not '03/04...
garaetjjte 3y ago
>Can it show pictures from the web? Even better, you can play Quake on it! https://www.lofibucket.com/articles/oscilloscope_quake.html https://www.lofibucket.com/articles/oscilloscope_quake.html